S2 E2: Debunking the BMI with Dr. Janet Tomiyama
The science is clear: diets don’t work. So why is the medical establishment still so obsessed with them? Virgie and Janet break it down.
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Virgie Tovar: [00:00:00] This episode has a discussion of the Body Mass Index and other medical language related to weight. If this is concerning for you, please take care.
I’m 15 years old. In a high school gym during the worst week of the school year: the Presidential Fitness Test, the yearly sadistic ritual where we are forced to perform acts of strength and flexibility in front of 30 other 15 year olds. The “V sit and reach,” the “pull-up test.” The “sit up test.” Then we all line up in our polyester uniforms, alphabetically by last name and get publicly weighed and measured by my PE teacher, Mr. Lafferty, who then yells the numbers to his clipboard-toting assistant in front of the whole class. The numbers echo ruthlessly into the cavernous gym. Tovar, Tovar, Tovar, like a canyon of shame. That's how I was introduced to the Body Mass Index. The BMI. Body Mass Index is the number you get when you weigh someone, and then measure how tall they are, then take the first number and divide it by the second number, squared.
The number is used to determine what weight category you're in. If you've ever been to the doctor, you've probably had your BMI taken. And whatever advice they give you is based on the number you are. You might be asking, how can anyone's overall wellbeing be boiled down to how tall they are and the number on a scale? That's two numbers! Surely that can't account for all the diversity of humankind?
Well, it turns out that it doesn't. I want to introduce you to someone whose work shows all the problems with relying on BMI as a health indicator. Her name is Janet Tomiyama. In fact, her career is basically committed to changing how academia thinks of weight.
My chat with Janet began– as so many of my favorites do– over a bag of crispy, salty, mouthwatering potato chips.
Janet Tomiyama: [00:02:39] Today I have, um, a white truffle and sea salt, potato chip. So I've never, like, actually had white truffle in my life. I think it's a little bit out of my price range. So I feel like this is a way that I can tap into some luxury.
VT: [00:02:54] Okay. Should we, should we, have you already opened yours? I haven’t opened my chips yet.
Okay, good. Yeah. Professional.
Okay. I love the smell. I like the smell coming out. Oh, it's good. Okay. Should we crunch together?
JT: [00:03:10] Yes.
VT: [00:03:11] Okay. Three, two.
[crunch and laughter]
We got the synchronize crunch, Janet, this is a good sign. We're potato chip sisters now!
JT: [00:03:29] I’m very happy to be your potato chip sister.
VT: [00:03:35] Janet is a professor and a health psychologist at UCLA, and she studies how biological, social, and psychological factors influence health. In other words, considering the whole person, including how you grew up, your mental health, your genetics, the kind of community you live in. Janet thinks all of that is important.
So you may not know this, but looking at social and psychological factors that influence health and illness is NOT super popular in medical science. The field, and, frankly, our culture, is obsessed with the individual taking full responsibility for their own health. Period. The end. It's at the root of some very powerful American ideology that mythologizes the possibility of “beating the odds” and says that no matter what, anyone can become anything they want.
If you just stop eating potato chips, you can be thin! If you can just lower your BMI, maybe you will be successful. If you learn how to play the numbers right, maybe you can even cheat death. It's like a feedback loop. And when everyone buys into it, then bam! You have a justification for things like diet culture.
And I hate to say it. But the medical world and the idea of quote-unquote health perpetuate this feedback loop. I found out about Janet because she is one of the few academics whose work is disrupting the feedback loop. Her research has shown that the hard empirical data says: diets do not work.
JT: [00:05:20] Let me just start with the research.
So we did a study that looked at every single study out there that looked at patients or participants who were put on a diet, and then what happened to their weight. What we found over and over again is that diets do not lead to long-term weight loss.
VT: [00:05:44] Okay. Anyone who has ever been on a diet knows that this is true.
So this doesn't surprise me, but what did surprise me is just how much some of her colleagues, fellow scientists, don't give the work the time of day. Because it undermines accepted beliefs in the medical world. Janet told me about the saga she went through to get one of her papers published. And this is important, because publication is the main way new science gets legitimized and spread. The paper reviewed all the existing science behind the question: do diets work?
JT: [00:06:23] We submitted it for publication, we didn't hear back, we didn't hear back. And the editor in chief reached out and said, you know, like, it's not that I'm sending it out for review and your peer reviewers are saying that the quality of the work isn't good. He's like, I just can't find anyone who's willing to review it.
Um, and he's like, I think it's because the topic is too dicey. Um, and so he's like, here's what I'm going to do. Cause I think the topic of your paper is important. He's like, I'm going to invite somebody to write an opposing piece to your paper, and I'm gonna write a bridging editorial to kind of, like, create some peace between the two camps and bridge the two camps. So it was only through this, like, divine intervention by the editor in chief, uh, that it ever saw the light of day. And, you know, even that was after many attempts at different journals. And I was presenting this work at a conference and someone came up to me and like, I was a grad student at the time. And she was, like, so angry with me. And she was, like, you have done a huge disservice to our field with this paper. Like what the fuck is going on?
And she's like, now nobody is going to believe that there's anything they can do to help their health. You've like, given everybody an excuse to just eat whatever they want.
And you know, so that like really shook me and I still remember it very vividly. So you can kind of see, like, how heated the argument is.
VT: [00:08:08] Here's a secret I learned in grad school. Academia is not committed to the pure pursuit of science. There are politics, favoritism, and university interests involved. I know, booooooo. It was like finding out that Santa isn't real when you're 30. And that was just Janet's first attempt to publish some anti-dieting research.
When she started studying weight stigma–the unequal treatment that people face simply because of the size of their bodies–she found herself in the middle of a fight over national public health policy.
JT: [00:08:46] So, initially most of the research was documenting the negative psychological effects of experiencing weight stigma.
So, you know, it should come as no surprise to anyone that if someone experiences weight stigma or, I guess the common term would be fat shaming. Someone experiences fat shaming, it makes them feel bad. And so there's plenty of research showing that weight stigma is, uh, predictive of and correlated with anxiety, depression, uh, decrements in self-esteem and things like that.
And that research came at a really important time because there was a sort of battle going on at the public health and medical ethicists level, where people were trying to say that, you know, actually we should be using weight stigma as a public health tool because, you know, making people feel bad about their size is a great way to motivate them to work out and eat healthier.
And so, you know, as a scientist, I was like, well, we need data on that. You know, is weight stigma really going to promote health or destroy it? And so what we found in a nutshell is when people experience weight, stigma, it doesn't lead to weight loss, actually it leads to weight gain. There are psychological effects, there are physiological effects.
And, you know, I think any policy that rests on making certain segments of your population feel bad because of the way they look, I, you know, I don't like that as a policy strategy in the first place. But this scientific evidence is showing it's not even going to work. It's going to backfire.
VT: [00:10:37] I mean, you and I have talked about this, and the position of the academy and the medical establishment, really is that sort of being a fat person is a pathology, is something that is inherently understood as a deviation, a failure, um, you know, and as a disease, right? And I'm kind of curious about your thoughts on that and what it's like doing this research in that environment.
JT: [00:11:07] Yeah. So what motivated us to study this question in particular was because the EEOC, which is the Equal Employment Opportunity Commission– they were about to rule on a law that would make it legal for employers to charge higher BMI employees more for their health insurance. So, the assumption there being anyone who has a BMI of 30 and above is unhealthy, so they're costing us more, so we have a right to charge them more for their health insurance.
And so we got wind of that and we were like, hmm, surely not everyone with a BMI of 30 and above is unhealthy. Surely it's not fair or justified to charge them more for health insurance. And so we did an analysis using some of the best data that's available in the United States called the NHANES. So National Health and Nutrition Examination Survey, and they have information on body mass index, and they also have information on all sorts of health indicators.
So things like, uh, blood pressure, cholesterol. So, all those markers that indicate poor health. And our analysis is actually pretty simple, it was, is there anyone with a body mass index of 30 and above who looked perfectly healthy on all these markers? And found that yes, in fact, there are lots of people who have an obese BMI who do not show any indication of poor health, uh, you know, millions, actually, of Americans fit that bill.
And so we concluded, uh, it's not fair to charge someone more for their health insurance, just because their BMI is above 30. And so basically we were like, EEOC, don't let this happen. Unfortunately, they did let it happen. So that is now law in the United States.
VT: [00:13:12] Wow. I did not know about this. I mean, that's, um, I'm just, I'm just having a moment with that.
It's like really intense to kind of, it's intense to, to think about it.
Janet and her colleagues found that with so much emphasis on BMI, one in five of all Americans are being misled about their health status. That's more than 70 million people. If BMI can do that, why use it? We shouldn't!
It turns out if you look at the history of BMI, it's actually incredibly outdated and unscientific. It was invented in the 1830s by a Belgian mathematician named Adolphe Quetelet.
Please note he was not a physician and he never intended the BMI to be a measure of health. He was, however, kind of obsessed with using math to define the “average man.” And by average, I mean, literally the average you learn to calculate in fifth grade math. Adolphe believed that average was the ideal.
Nevermind the fact that he was basing his calculations on a super limited set of subjects. So convinced was he that the hypothetical average white man embodied perfection, that he once said, and I quote, “Everything differing from his proportion or condition would constitute deformity or disease or monstrosity.”
Yikes. From there, it didn't take long before things got super racist. His work was used to underpin phrenology and eugenics, the racist science that Nazis used to justify the Holocaust. That's also been responsible for the forced sterilization of people of color and disabled people. But the real kicker is that it is still used today, to make health assessments. And it is not working.
Let me give you just one example. I want to tell you about Rebecca Hiles. Around 2010, she was a plus-size teen who started having coughing fits and shortness of breath. When she went to the doctor, she was told these problems were because of her weight. But it turned out, she had lung cancer. And the doctors missed it, because they didn't check.
I've spoken to dozens of fat people who've experienced some version of this story. Fat people are being prescribed diets every day to solve every problem under the sun. I don't know if I need to say this, but last time I checked restricting food doesn't cure things like cancer.
I remember being an 11 year old kid on the cusp of entering sixth grade. I had seen every teenage transformation movie and I wanted my final year of elementary school to be epic. All I wanted was for the boys at school to stop bullying me, and to be thin and beautiful, so I could finally find a boyfriend. I knew I didn't have much time–only as long as summer vacation. So I basically stopped eating. Whenever I was hungry, I allowed myself lettuce, toast, and a little bit of barbecue sauce to flavor it. I did a VHS exercise tape two or three times a day, every single day for three months. By the time the summer was over, my body was really different. But instead of questions, or alarm, all I got was praise. Even from our family physician, who told me that if I kept up the good work, I might be allowed to date one of his sons. REALLY??
Moral of the story: medicine can be super fatphobic. And fat people can feel it. Janet's work has shown that fatphobic medicine makes people avoid going to the doctor when they're sick. We changed doctors more often, too, because of how we're treated. When we do go to the doctor, we often get weight loss advice, which makes us feel shame and failure.
This is fatphobia at its most dangerous. More with Janet after the break.
[midroll]
We're back. Before the break, I was telling you about how fatphobia in medicine has devastating consequences. To the point where it sometimes seems like following doctors’ orders can cause more harm than good.
JT: [00:18:10] I just want to connect it back to weight stigma, where people sort of hide behind concerns for someone's health as a way to kind of make it okay for them to stigmatize. So they'll say, Oh, you know, it's not that I don't like the way you look, I'm just really worried about your health, you know? And so I think this, um, confusion surrounding what health is and whether or not you can be healthy at a larger size, it's really making it easy to stigmatize other people for their weight.
And so, I did a study where I randomly assigned people to diet or not, and I measured their levels of the stress hormone cortisol. And what I found, that yes, if you cut calories, your stress hormone levels go up. And we know that stress, ironically, makes you gain weight. And so that's one reason why dieting is just such a futile endeavor to try and do.
VT: [00:19:05] We have this idea that dieting and weight loss are, or, you know, the pursuit of weight loss is this health-promoting behavior, that restricting food is health-promoting. But our bodies, they experience it as a threat to our survival. As somebody who literally made herself ill while dieting and couldn't understand why– I couldn't understand why I was ill, and there was a lot of cognitive dissonance that led to me continuing to diet, despite the correlation between the more I restrict, the sicker I get. Um, and I just couldn't bridge those two realities, you know?
JT: [00:19:49] If you look in our evolutionary past, like, our main challenge was getting enough food to eat. And so of course your body is not going to understand no, no, no, I'm just doing it so I can look better in the eyes of society, you know? Um, so your body does see that as a threat that it needs to contend with. And one of the jobs of the stress hormone cortisol is to signal your body to store fat. I think what you're saying, in terms of when heavier individuals lose weight, it gets even more complicated because all you get when that happens is a ton of praise.
So like I see it with my husband, who due to the stress of quarantine and worrying about our four-year-old child and what to do about school opening and all that stuff, um, has lost 20 pounds since March. And so when we see other people–socially distanced, of course–they're like “Ah, you look great! What have you been doing? Awesome!”
And I’m like, when I hear it, I'm just horrified because of my research, you know, I'm like, no, no, it’s horrible things that have led to this weight loss!
VT: [00:21:04] You don't need me to tell you that COVID has created a huge disruption in our patterns, and a spike in weight and food anxiety. It's made us feel scared for our safety and looking for means of control. For a lot of people, including me, that has meant falling back on old patterns of controlling what I ate.
Which leads to situations like the one Janet just described. So I'm just going to say it: important takeaway from this episode, the question “have you lost weight?” is NOT a compliment.
JT: [00:21:42] We assume that weight and health are the same exact thing. If somebody loses weight, then that's a success. And if they don't, then that intervention was a failure.
And so, I can give you an example of this. This was an amazing study done by John Blundell and colleagues, um, where they brought people in and had them exercise in the lab in front of everybody. And they looked at their actual health indicators. So things like blood pressure. Um, and what they found is that, regardless of whether you lost weight or not, everyone who is in this exercise condition improved on their health markers.
So that's great news, because it doesn't matter what the number on the scale is. You're still seeing improvements and health. And so, I read that study as like a super good news study. Like finally, we can get rid of this fixation on weight and, like, really focus on what's important. And this study shows us that we know that exercise is going to be helpful.
But the reason I bring up this study is because the title of this study was literally “Exercise is Not Enough.” And so even in the study authors’ minds, their study was a failure because not everybody lost weight, they just sort of cycled right back to that weight-centric viewpoint of you got to lose weight or else it's a failure.
VT: [00:23:09] It's– I mean, I think what's, so what always blows my mind, as someone who has, you know, gone to grad school and experienced the rigor, um, of, you know, so many of the research protocols, and to just kind of get to weight stigma, it's like the precision, the science, it just goes right out the window.
There's like no consideration of data. There's no consideration of accuracy. There's no consideration of, you know, like, well, like what bias is going into this? What, you know, how are you defining this term? And are there problems with that definition? And it's just mind boggling to me, you know?
JT: [00:23:49] Agreed. Um, the whole reason why we did that analysis is because in response to our “dieting doesn't work” paper, people said, well, sure, maybe it's hard for everyone to lose weight on a diet, but you know, the people who do actually manage to lose weight, they're so much healthier. And we're like, is that even true?
And we found that across all the studies that we studied, um, that has, again, long-term outcomes, two years or more, that the amount of weight you lose on a diet is not related to any health improvements. But the people who lodged that criticism at us, you know, their viewpoint is: sure, maybe that one diet didn't get everyone to lose weight, but if we could just find the perfect diet, that's the solution.
And so they're still stuck in diet land. You know, when our argument is, let's sort of let this thing go, nobody likes doing it, it doesn't work. It's increasing levels of your stress hormones. But again, as long as you are cementing in your brain, that weight equals health, it's doing a disservice to the public health of our nation.
VT: [00:25:02] But why, why are we stuck in diet land?
I give lectures about this all the time, to rooms full of smart people. I show them the facts of what fatphobia and weight discrimination do to people. Fat women make less money than thin women, a disparity that starts at $9,000 annually. Fat people are seen as less intelligent and capable by the academics who get to decide who gets a PhD.
Fat shaming and dieting are connected to eating disorders, anxiety, depression. Devastating numbers of fat people don't leave their homes, because they're afraid of being abused. And the list goes on and on and on. Then when time for Q and A comes, the first question from the audience without fail is almost always: but what about health?
As if all that I've just shared doesn't matter if the person experiencing these spirit crushing things,doesn't have a clean bill of health? To me, as a person who has always been fat, who almost destroyed her health, attempting to be the version of healthy that I know they're talking about, this question is so gravely offensive and hurtful. It so totally misses the point of what I'm arguing for, which is human rights. We cannot make health a condition of human rights. Beyond that, health is actually not something that people can achieve 100% on their own. Literally the CDC even knows it.
I want to share with you a fact that changed my life. The Centers for Disease Control note that individual behaviors only account for 30% of our overall health. That means that a whopping 70% of the things that determine how long we live and our quality of life are social factors that are out of our control. Like whether we have access to public transportation, whether we experienced trauma in childhood or whether we experienced discrimination. Why, please tell me, aren't we as obsessed with shifting what's in that 70% as we are with vegetables and exercise? We do not owe other people our health. All people, regardless of size, have the right to feel like they have tools to build their definition of their best life based on what resources they have access to, and receive good medical care when they're sick.
Besides, what is more health promoting than paying someone equally? Or screening them properly for medical care? What is more health promoting than treating someone like they're a human being? Sadly, right now, I don't live in a country where those basic things are available to everyone. So the question becomes, how do we get there?
Okay. Here's the $10 million question. Because the word health has been weaponized against me and people I care about, and so many people. How do we end weight stigma and also create this possibility for people to live the highest quality of life that they, you know, they can have?
JT: [00:28:51] I'm so glad we're talking about this, because I still struggle with what's the best way to talk about it?
Um, even with my paper that we talked about earlier, showing that there are millions of Americans with a BMI in the obese range who are healthy, you know, I've been criticized for that work for saying that there are good fatties and bad fatties and the bad fatties are the ones who have poor health markers as if they're, like, worth less.
And I totally hear that. And I think it's a valid criticism of this work. It's still putting health as like this holy grail that we're trying to achieve at all costs.
VT: [00:29:36] Yeah, I'm going to, and I think, you know, for me, it's like, I do believe that every single person, especially in a culture that is so focused like that doesn't have universal healthcare. I'm like, if you don't have universal healthcare, you don't have shit to say to anybody. I'm sorry. Like, that's just like, it's just done. Like, you clearly have shown that you're not willing to put money behind people's lives. So you get to shut up forever now. That's my opinion.
Um, but like, you know, so, so specifically, right, there are people who literally you cannot access health. Um, whether it's because of the fact that they don't even have space for that, the bandwidth, right? Look, for somebody who's in survival mode, that is not a priority, survival as a priority, or you're in survival mode. And there are so many people by virtue of how our society or culture is structured, who are living in that reality every single day.
And then I think about somebody like my own family who, you know, I grew up in the suburbs. My family is an immigrant family. There was a huge amount of intergenerational trauma. And I remember having this conversation with my mother about how much she loved like strawberry soda or something like that.
You know, she liked the color and all this stuff. And then, but she specifically said, It makes me feel happy and I can feel it like when it's entering my body, that it's giving me happiness. And she didn't have a lot of access to joy for so many reasons, right? Like, had mental illness and she's a fat person and she's a woman and, um, you know, and all these different layers.
And I think there are people who would look at that and pathologize her. But, there's another side of her story where she's, she is doing the most intuitive, natural thing in the world, which is to find things that make her feel good, that offset experiences of suffering. And that is genius. That is brilliant. That is exactly how the body was designed to interact with the world.
And I'm so deeply aware. For me, food symbolizes freedom from that life where I felt like trash and my– because I wasn't thin– and food represents that to me. It's like, it's not only this, like experience of joy and love and sharing and community, which I have the privilege of having that experience.
But it also has this other layer where I'm like, you will not tell me how to eat. And that is how I maintain dignity. And dignity is significant for a person's mental health. And I think for me, I'm just like, how gorgeous, right? Like, how gorgeous is it that someone who is against– like has so many odds stacked up against them, is able to sort of say, like, I know exactly how to get that little thing that's going to make this moment feel okay, or it's going to give me dignity, you know? And I just, I feel like there's not room for this conversation, Janet.
JT: [00:32:43] I resonate with so much of what you just said. And in fact, some of it sounds like a non-scientific version of what I've written in some of the introductions to my scientific papers.
It makes me think of a story that Rob Lustig who's a very famous endocrinologist at UCSF. Um, told me once, which was he went to Bayview/Hunter’s Point, which you probably know is sort of a, uh, lower income, um, majority racial minority area of San Francisco. And he did sort of his classic spiel of like, This is what nutrition is, and here are the foods you should be eating. And here are the foods you shouldn't be eating. And at the end of his nutrition lecture, a woman raised her hand and she was like, I work two jobs. Uh, the one pleasure I have in life is my Snickers bar that I get to eat at the end of the day. And are you saying you're going to take that away from me?
VT: [00:33:40] Yes.
JT: [00:33:41] And it's like, yeah, who are we to say that that is so wrong and shake our finger at this woman for coping in the way that as you said, is very beautifully adopted to her environment because it's available and cheap, um, and is consistent. It's gonna work every time.
VT: [00:34:01] Janet, I want to say thank you for being on Rebel Eaters Club and for your incredible work and for illuminating us about so many amazing things.
JT: [00:34:11] Thank you. I'm so excited to actually get to talk to you. And this is definitely the best part of my day.
VT: [00:34:23] Hundreds of years of scientific inquiry, went into creating a world where we have so-called good food and bad food, good bodies and bad bodies. But just because that work is filed under “science” doesn't mean it shouldn't be scrutinized. Because yes, even doctors and scientists like us live in diet culture, too.
I'm not telling you all this, just so you know that there are serious problems with our culture. Though that's important, I'm telling you all this, because we have to face it if we're going to fix it. The day of data existing and being gathered in the name of creating the right body and the wrong body has to end. Data that ends up becoming the basis for people not getting care–
it's got to come to a close. Science not only should do better, it can do better. Janet is proof that there is hope and she's proof that we can get in the trenches and fight for the right thing even if it's unpopular. It's going to take a lot for us to get the world we deserve. One that's more free and fair and– hello– fun! But the pleasure we get when we bite down on the perfect potato chip, that honest, innocent, purely human pleasure. I have a feeling it's going to help us figure out how to bring the whole thing down.
Okay. There's one truly amazing fact in my research that I saved for you for the very end. I found it in the Journal of Texture Studies, which publishes articles with truly magical titles like: “Effect of Pectin Content on Flow Properties of Mango Pulp.” What I want to share comes from one entitled: “Analysis of Food Crushing Sounds During Mastication.” Researchers found that the sound of chewing, AKA mastication, on potato chips gives people pleasure. And in fact, we maximize the sound our mouths make.
Participants who wore headphones weren't as into their chips, as those who could hear themselves. And that one tiny little act of crunch joy, I think, means there's still hope for us yet.
Rebel Eaters Club is produced by Transmitter Media. Our lead producer Jordan Bailey loves sour cream and onion and potato chips. Lacey Roberts is our managing producer and she can't live without those crinkle cut kettle chips with salt and pepper. Sarah Nics edits the show. And she loves ketchup chips because she's Canadian. And our executive producer Gretta Cohn loves a dill pickle chip. Specifically with beer.
I'm your host, Virgie Tovar, and I love salt and vinegar. Ben Chenault is our mix engineer. Special kudos to James T. Green and Jessica Glazer for the production assist. And to Taka Yasuzawa who wrote some of the music we use in the show. If you love Rebel Eaters Club, tell your friends and share the love by writing a review on your favorite podcast app.
See you next week.